LSI (Large Scale Integration) circuits are semiconductor integrated circuits which have over 1000 elements, and ULSI or the like are those which have over one million elements stored on a single chip, and in recent years, 100 million or more elements have been formed on a single chip.
This type of ULSI cannot be accommodated simply by miniaturizing elements on a plane, so multiple layer wiring construction with a plurality of overlapping layers of wiring has become essential. A multiple layer wiring construction increases the capacitance between layers and causes the elements to have longer signal delay times, so in order to reduce the capacitance between layers, a low dielectric constant inter layer insulating film (herein after referred to as Low-K film) is used as an insulating film between layers.
On the other hand, in the ashing process which removes the resist mask that is no longer required after patterning the Low-K film on a wafer that has exposed Low-K film, a gas that includes hydrogen which is a reductive gas is used as the ashing gas in order to minimize the increase in the dielectric constant of the Low-K film that is caused during ashing.
Furthermore, in addition to the aforementioned case, processing by reductive plasma represented by hydrogen plasma is performed during the manufacturing process for semiconductor manufacturing devices (For instance refer to patent documents 1 and 2), and processing using a hydrogen plasma is performed in the manufacturing process for liquid crystal display devices (for instance refer to patent documents 3 and 4).
Patent Document 1: Japanese Laid-open Patent Application H6-140368
Patent Document 2: and Japanese Laid-open Patent Application 2003-124311
Patent Document 3: Japanese Laid-open Patent Application H5-152333
Patent Document 4: Japanese Laid-open Patent Application H6-330283
Patent Document 5: Japanese Laid-open Patent Application 2004-111731